Week 3:

The world of microorganisms

Fungi

Friday, January 2, 2015

Biochemistry, Microbiology and Immunology

2

Taxonomy:naming and classifying living organisms

Bacteria 4 µm 100 µm

0.5 µm

Kingdom PlantaeProtists?

Kingdom AnimaliaKingdom FungiArchaea

3 Domains and 5 KingdomsDomain 1: Bacteria

Domain 2: Archaea

Domain 3: Eukarya

Kingdom Monera

3

Taxonomy:naming and classifying living organisms

Domain Bacteria Domain Archaea Domain Eukarya

Kingdom Monera Protista ??

MostlyUnicellular

Multicellular

HeterotrophsAutotrophs

Absorb food Ingest food

Kingdom Animalia

Kingdom Plantae

Kingdom Fungi

4

Bacterianumerous and omnipresent

Bacterial population in a handful of soil:

60 billion10,000 species

Human population in the World:

6 billion1 species

5

BacteriaSize Compared with Viruses and Eukaryonts

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Bacteria: Did you know?

#1 threat: The handles of

almost two-thirds of

shopping carts tested in a

2007 University of Arizona

study were contaminated

with fecal bacteria.

-The carts had even more

of these bacteria than the

average public bathroom

has.

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Kingdom: Monera or

Eubacteria• There are 182 different types of

bacteria located on your skin.

• Sweat glands excrete

lysozyme, which lyse (break

open) certain types of bacteria.

8

BacteriaLack of membranous organelles

A typical

rod-shaped

bacterium

A thin section through the

bacterium Bacillus

coagulans (TEM)

0.5 µm

Pili

Nucleoid

Ribosomes

Plasma

membrane

Cell wall

Capsule

Flagella

Bacterial

chromosome

9

BacteriaNutrition

10

BacteriaReproduction

Cell wall

Plasma

membrane

Bacterial

chromosome

E. coli cell

Chromosome

replication begins.

Replication continues.

Replication finishes.

The plasma membrane

grows inward, and

new cell wall is

deposited.

Two daughter

cells result.

Binary Fission

11

Bacteria in the BiosphereDecomposers

Cellular

respiration

Burning of

fossil fuels

and wood

Carbon compoundsin water

Photosynthesis

Primaryconsumers

Higher-levelconsumers

Detritus

Decomposition

CO2 in atmosphere

Decomposition

• Decomposition is the natural process of

dead animal or plant tissue being rotted or

broken down. This process is carried out

by invertebrates, fungi and bacteria.

13

Bacteria in the BiosphereFood for Other Species

5 mm

Earthworm

0.1 mm

Stentor, a unicellular

•To which Kingdoms do these organisms belong?

•Would you eat Bacteria?

14

Bacteria in the BiosphereSymbiosis

~1000 species of bacteria live in the human intestines helping in :•Food digestion•Production of vitamins•Protection against pathogens

Probiotics are dietary supplements of live microorganisms thought to be healthy for the host organism.

Prebiotics are non-digestible food ingredients that stimulate the growth or activity of bacteria in the digestive

system which are beneficial to the health of the body. (fibers).

The term symbiosis (from the Greek: σύν syn "with"; and βίωσις biosis "living") commonly describes close and

often long-term interactions between different biological species.

Symbiosis or mutualism

• Mutualism is any relationship between

individuals of different species where both

individuals benefit.

• Humans have a mutualistic relationship

with microorganisms, primarily bacteria, in

their digestive tract. Bacteria make

vitamins for human and help in digestion

of food. In return they use the food in

human digestive system.

17

Bacteria in the BiosphereFixing Nitrogen

Assimilation

N2 in atmosphere

DecomposersNitrifyingbacteria

Nitrifyingbacteria

Nitrogen-fixingsoil bacteria

Denitrifyingbacteria

NitrificationAmmonification

Nitrogen-fixingbacteria in rootnodules of legumes

NO3–

NO2–NH4

+NH3

Nitrogen fixing

• Earth's atmosphere is approximately 78-80% nitrogen,

making it the largest pool of nitrogen. Nitrogen is

essential for many biological processes; it is crucial for

any life here on Earth. It is in all amino acids, is

incorporated into proteins, and is present in the bases

that make up nucleic acids, such as DNA and RNA. In

plants, much of the nitrogen is used in chlorophyll

molecules, which are essential for photosynthesis and

further growth.

• Bacteria convert atmospheric Nitrogen into the proper

chemical form of Nitrogen that is essential for the growth

of plants.

19

Bacteria in the BiosphereReleasing Oxygen

21

Bacteria in the BiosphereReleasing Oxygen

The cyanobacterium Anabaena, a colonial prokaryote

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The Importance of Bacteria

Many antibiotics are

produced by bacteria.

23

Bacteria in the BiospherePathogenic bacteria

Anthrax Bacterial Meningitis Botulism Brucellosis CampylobacteriosisCat Scratch Disease Cholera Diphtheria Epidemic Typhus GonorrheaImpetigoLegionellosisLeprosyLeptospirosis

ListeriosisLyme disease MelioidosisRheumatic FeverMRSA infection NocardiosisPertussisPlague Pneumococcal Pneumonia Psittacosis Q fever Rocky Mountain Spotted Fever (RMSF)

SalmonellosisScarlet Fever Shigellosis Syphilis Tetanus Trachoma Tuberculosis TularemiaTyphoid Fever TyphusUrinary Tract Infections

25

Bacteria in the BiospherePathogenic Bacteria

Listeriosis outbreak in Canada, 2008The 2008 Canadian listeriosis outbreak

was a widespread outbreak of listeriosis in

Canada linked to a Maple Leaf Foods plant in

Toronto, Ontario. Twenty-two people died and

there were 57 total confirmed cases.

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Archaebacteria

Archaebacteria “Ancient bacteria”

a. Life's Extremists! -hydrothermal vent (680 degrees Fahrenheit)

Archaea are found in the harshest environments on Earth

1/2/201527

Characteristics of

BacteriaCommon bacteria shapes:

a. Rod-shaped (bacillus)

b. Round (coccus)

c. Spiral-shaped (spirillum)

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Coccus Shaped

Bacteria

29

Spirillium Shaped Bacteria

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Drug-Resistant

Bacteria

31

Let's Recap

1. The distinctive characteristics of the Kingdom Monera are the small size, the lack of membranous organelles and the presence of a cell wall with unique biochemical composition.

2. The nutritional and metabolic diversity of Bacteria is appreciated in the their different nutritional modes, different oxygen requirements, and efficient reproduction modes.

3. The major roles played by Bacteria in the Biosphere are:

a) Decomposers: b) Food source: c) Symbiosis: make a beneficial relationship with other living

organisms, e.g. bacteria in human large intestine help in digestion of food and making vitamins and in return they obtain food from human

d) Oxygen release: e) Nitrogen fixation: f) Pathogens:

ProtistaA world in a drop of water

Distinguishing characteristics of ProtistsAre more diverse than all other eukaryotes and are no longer classified in a

single kingdom. Protists contain Cells with a nucleus and membranous

organelles

5 µmEuglena (LM)

Plasma membrane

Nucleus

Short flagellum

Eyespot

Light detector

Contractile vacuole

Chloroplast

Paramylon granulePellicle

Long flagellum

(Euglena: All have flagella)

Distinguishing characteristics of ProtistsMostly unicellular, except for algae and colonies

20 µm50 µm

Volvox, a colonial freshwater chlorophyte

Calperpa, an inter-tidal chlorophyte

Ulva, or sea lettuce Or Green algae

Or Green algae

Distinguishing Characteristics of ProtistsAquatic Habitat

Ceratium tripos, a marine dinoflagellate

Trichomonas vaginalis, a parasitic parabasalid

Spirogyra, a freshwater green alga

Dictyostelium discoideum, a slime mold

ProtistsNutrition modes

Plant-like protists

Animal-like protists

Fungi-like protists

Euglena Macrocystitis

Ingest food

Absorb food

Amoeba

Slime mold

ProtistsThe Algae

•Green Algae

•Fresh water, marine and terrestrial

•Chlorophyll a & b

•Carotenoids

•Both uni- and multicellular

•Brown Algae

•Almost exclusive marine

•Chlorophyll a & c

•Xantophylls, Fucoxanthins

•Mainly multicellular

•Red Algae

•Mostly marine

•Chlorophyll a

•Phycocyanins, Phycoerythrin

•Multicellular

Spirogyra

Chlorophyta

Delesseria sanguinea

Rhodophyta Phaeophyta

Laminaria

Ceratium tripos, a marine dinoflagellate

Trichomonas vaginalis, a parasitic parabasalid

Spirogyra, a freshwater green alga

Dictyostelium discoideum, a slime mold

ProtistsEcological Roles

Food source for other species Oxygenrelease

Pathogen

Decomposer

Pathogenic Protists

Let's Recap

1. Protists are Eukaryotic, mostly unicellular organisms that live in aquatic environments and form cysts in response to adverse environmental conditions.

2. Protists have diverse modes of nutrition: autotrophic (photosynthetic) and heterotrophic (ingestive and absortive).

3. Euglena, Paramecium and Ameba are examples of unicellular protists, while Volvox and some slime molds are examples of colonial protists.

4. Algae are divided in three groups based on the type of photosynthetic pigments:

a) Chlorophyta or green algae

b) Rhodophyta or red algae

c) Phaeophyta or brown algae.

Let's Recap (cont.)

5. The major roles played by Protists in the Biosphere are:

a) Decomposers: E.g. Slime molds

b) Food source: E.g. Planktonic and soil protists

c) Oxygen release: E.g. Chlorophyta

d) Pathogens: E.g. Trichomona

42

Kingdom Fungi

43

Taxonomy: naming and classifying living organisms

Domain Bacteria Domain Archaea Domain Eukarya

Kingdom Monera Protista?

Unicellular Multicellular

HeterotrophsAutotrophs

Absorb food Ingest food

Kingdom Animalia

Kingdom Plantae

Kingdom Fungi

Unicellular+ Algae

Multicellular+ Yeasts

44

Kingdom FungiComparison with Plants and Animals

Multicellular Eukaryonts Multicellular Eukaryonts Multicellular Eukaryonts

Mostly immobile Mostly immobile Mobile

Heterotrophic (no chlorophyll) Autotrophic (chlorophyll) Heterotrophic (no chlorophyll)

Absorptive nutrition - Ingestive nutrition

Lack of motile sperm Some have motile sperm All have motile sperm

Cell walls made of chitin Cell walls made of cellulose Lack of cell walls

Fungi Plantae Animalia

45

Kingdom FungiStructure

Reproductive structure

Hyphae

Spore-producingstructures

Mycelium

20 µm

46

• Decomposers can consume almost any carbon-containing substrate.

› Fungi and bacteria are primarily responsible for

keeping ecosystems stocked with the

inorganic nutrients essential for plant

growth.

› Without these decomposers, carbon, nitrogen,

and other elements would become tied

up in organic matter.

› Plants and the animals that eat them could not

exist because elements taken from the

soil would not be returned.

Fungi as decomposers

47

Kingdom FungiNutrition

Hyphae adapted for trapping and killing prey

Fungal hypha

Haustorium

Plant cell

Haustoria

Plant cell

plasma

membrane

Plant cellwall

NematodeHyphae 25 µm

Saprobes

•Absorb food from dead organisms.

Parasites

•Absorb food from living organisms.

48

Fungi in the BiosphereDecomposers

Cellular

respiration

Burning of

fossil fuels

and wood

Carbon compoundsin water

Photosynthesis

Primaryconsumers

Higher-levelconsumers

Detritus

Decomposition

CO2 in atmosphere

Shelf fungi

rhizopus

49

Fungi in the BiosphereSymbiosis: Mycorrhizae

Mantle

(fungal sheath)

Fungalhyphaebetweencorticalcells

Mantle

(fungal

sheath)

a symbiotic association of the mycelium of a fungus with the roots of certain

plants. Fungi provides the essential elements for plants from soil and in

return takes the food from plants.

50

Fungi in the BiosphereSymbiosis: Lichens

Fungal hyphae

Algal cell

Soredia

Algallayer

Fungalhyphae

Ascocarp of fungus

10

µm

a symbiotic association of

the mycelium of a fungus,

with alga

51

Fungi in the BiospherePathogenic Fungi

Corn smut on corn Tar spot fungus of sycamore leaves Ergots on rye

Fungal diseases in plants

52

Fungi in the BiospherePathogenic Fungi

Fungal diseases in animals(Mycosis)

Allergic bronchopulmonary aspergillosisAspergillomaAspergillosisAthlete's footBasidiobolus ranarumBlastomycosisCandidiasisChytridiomycosisCoccidioidomycosisCovered smut (barley)CryptococcosisCryptococcus gattiiDermatophyteDermatophytidsDermatophytosisDimorphic fungiEndothrixEntomopathogenic fungusEpizootic lymphangitisEsophageal candidiasisExothrixFungemia

HistoplasmosisJungle rotMassospora CicadinaMycosphaerella fragariaeMyringomycosisOnychomycosisOral candidiasisParacoccidioidomycosisPneumocystis pneumoniaRingwormSirococcus clavigignenti-juglandacearumSporotrichosisTinea barbaeTinea capitisTinea corporisTinea crurisTinea facieiTinea manuumTinea nigraTinea versicolor

53

Fungi and AnimalsCommon Evolutionary Origin

FungiEarly animals

(sponges)

Ancestral flagellated

Loss of flagellaDevelopment of chitin cell walls

54

Let's Recap

1. Fungi are Eukaryotic, vastly multicellular heterotrophic (absorptive) organisms that lack mobility and have cell walls made of chitin.

2. The structure of Fungi includes an externally visible reproductive stage and a network of filaments (hyphae) forming the vegetative stage or mycelium.

3. Fungi are divided in three major phyla: Zygomycota, Ascomycota and Basidiomycota.

4. The major roles played by Fungi in the Biosphere are:

a) Decomposers: E.g. Common black mold (Rhizopus)

b) Symbionts: E.g. Mycorrhyzae and Lichen [fungus + alga]

c) Pathogens for plants and animals: E.g. Candida

d) Food for other species: E.g. mushrooms

5. The current model of evolutionary origin of Fungi involves a common heterotrophic flagellated ancestor with Animals.